I have a solution file with a bunch of C# projects. For some of the projects, VS2017 urges me to upgrade the project to a later version. We are in a transition phase where one solution needs VS2017 while the rest of our code base is still using VS2015, hence we don't want to upgrade yet.
I do not understand why some projects are triggering this prompt and some not. They have the same ToolsVersion, ProjectTypeGuids, TargetFrameworkVersion etc.
I am looking for a way to modify the projects so that VS2017 shuts up until we are ready to make the full move to VS2017.